Currently, most nonwoven fabrics of chemical synthetic fiber are produced from melted macromolecule polymers and made by spunlaid process through extrusion and stretch to form continuous filaments as well as stacking laying for web formation so that the nonwoven fabrics of such filaments feature in good physical properties of air permeability and water absorption. Thus, such nonwoven fabrics of chemical synthetic fiber are prevalently used in application fields of medical, sanitary, wiper, filters and so on. According to the survey and statistics of Association of the Nonwoven Fabrics Industry USA (INDA), the marketing share for the nonwoven fabrics of chemical synthetic produced spunlaid process already from 33.5% in 1994 (second) leaps up to 43.7% in 2009 (first) with total annual yield of 2.7 million tons. Wherein, main raw materials are from polypropylene (PP), polyester (PET), polyethylene (PE) and Nylon in quantity order with overall consumed quantity 96%. However, the wasted nonwoven fabric of chemical synthetic fiber after having been used incurs a malignant impact to the environment because they are indissoluble by natural environment.
Chitin and Chitosan are linear polymers (namely linear-chained macromolecule polymers) produced from N-acetyl Glucosamine monomer and Glucosamine monomer by β-1,4 bond. Materials containing chitin widely distributes in the natural world such as horny shells of shrimps and crabs in crustaceans, etc. From viewpoint in food processing of waste recycling, Chitin and Chitosan are worthwhile to capitalize on exploitation. Moreover, the yield and output value for crustacean processing of shrimp and crabs is a primary project of aquatic product processing in Taiwan for quite a long time. However, the processing wastes, which abundantly contain protein, astaxanthin, chitin and the like, might become an ecologic and environmental burden if they have not been well treated. On the other hand, if they can be well exploited to process into chitin/chitosan, they may not only solve the waste issue but also create economical value with multiple beneficiary effects such as anti-mildew, bacteriostatic and deodorizing functions owing to their intrinsic biodegradibility and bio-compatibility. For processing horny shells of shrimp and crab in crustacean, 20˜30% of chitin therein can be obtained by proper purification while various chitosan with different degree of de-acetylating can be obtained via de-acetylating process under high temperature with hot alkali.
Therefore, how to produce nonwoven fabrics of continual filament with excellent anti-mildew, bacteriostatic and deodorizing functions by short eco-friendly process of low manufacturing cost from natural fiber material becomes an urgent and critical issue. Having realized and addressed above issue, the inventor of the present invention has been enthusiastically performing study and research in painstaking manner for quite a long time. Eventually, a satisfactory nonwoven fabric of continual filament with excellent anti-mildew, bacteriostatic and deodorizing functions is successfully worked out as disclosed in this specification.